Sustainable Development

Energy and sustainable

development • Worldwide, politicians, industrialists,

Sustainable development can be environmentalists, economists and theologians

affirm that the principle must be applied at
broadly defined as living, producing
international, national and local level.
and consuming in a manner that meets
the needs of the present without • The aim of sustainable development is for the

compromising the ability of future improvement to be achieved whilst maintaining the

ecological processes on which life depends.
generations to meet their own needs
• At a local level, progressive businesses aim to report
a positive triple bottom line, i.e. a positive
contribution to the economic, social and
environmental well-being of the community in which
they operate.
• Reliable energy supply is essential in all economies for lighting,
heating, communications, computers, industrial equipment,
transport, etc.

• Purchases of energy account for 5–10% of gross national product

in developed economies.

• However, in some developing countries, energy imports may have

cost over half the value of total exports; such economies are
unsustainable and an economic challenge for sustainable
development.
 Increase in energy consumption
• World energy use increased more than tenfold over the 20th
century, predominantly from fossil fuels (i.e. coal, oil and gas) and
with the addition of electricity from nuclear power.
• In the 21st century, further increases in world energy consumption
can be expected, much for rising industrialisation and demand in
previously less developed countries.
Stocks of Fossil fuels • The location and the amount of such stocks depend on
the latest surveys.
Fossil fuels are not being
• Clearly the dominant fossil fuel type by mass is coal,
newly formed at any with oil and gas much less.
significant rate, and thus
present stocks are • The reserve lifetime of a resource may be defined as
ultimately finite. the known accessible amount divided by the rate of
present use.

• By this definition, the lifetime of oil and gas resources

is usually only a few decades; whereas lifetime for coal
is a few centuries.

• Economics predicts that as the lifetime of a fuel

reserve shortens, so the fuel price increases;
consequently, demand for that fuel reduces and
previously more expensive sources and alternatives
enter the market.
Unsustainable use of fossil • For example, increasing
fuels concentration of CO2 in the
atmosphere.
The emissions from fossil • From, an ecological understanding of
fuel use (and indeed nuclear our Earth’s long-term history over
power) that increasingly billions of years, carbon was in
determine the fundamental excess in the Atmosphere
limitations.
• Needed to be sequestered below
ground to provide our present
oxygen-rich atmosphere.
• burning the fossil fuels imply
that current patterns of use are
unsustainable in the longer
term.
 Long-term effects
Since, CO2 emissions from the combustion of fossil fuels have
significantly raised the concentration of CO2 in the Atmosphere.
The balance of scientific opinion is that if this continues,
• it will enhance the greenhouse effect
• and lead to significant climate change within a century or less,
• which could have major adverse impact on
• food production,
• water supply and human, e.g. through floods and cyclones .
Recognising, that this is a global problem, which no single country can avert on

its own, over 150 national governments signed the UN Framework Convention

on Climate Change, which set up a framework for action on the issue. Sadly,

concrete action is slow, not least because of the reluctance of governments in

industrialised countries to disturb the lifestyle of their voters. However,

potential climate change, and related sustainability issues, is now established

as one of the major drivers of energy policy.

In practice, many other factors are involved, especially
• governmental policy
• international relations.
Nevertheless, the basic geological fact remains: fossil fuel reserves
are limited and so the present patterns of energy consumption and
growth are not sustainable in the longer term.
Therefore from arguments of
i. the finite nature of fossil and nuclear fuel materials
ii. the harm of emissions and
iii. ecological sustainability,
it is essential to expand renewable energy supplies and to use
energy more efficiently.
Renewable energy supplies are much more compatible with
sustainable development than are fossil and nuclear fuels, in
regard to both
i. resource limitations
ii. and environmental impacts.
Consequently almost all national energy plans include four vital
factors for improving or maintaining social benefit from energy
✓1 increased harnessing of renewable supplies
✓ increased efficiency of supply and end-use
✓reduction in pollution
✓ consideration of lifestyle.
 Fundamentals
Renewable energy. Non-renewable energy.
‘Energy obtained from natural and ‘Energy obtained from static stores
persistent flows of energy occurring in of energy that remain underground

the immediate environment’. An unless released by human

obvious example is solar (sunshine) interaction’. Examples are nuclear

fuels and fossil fuels of coal, oil and
energy, where ‘repetitive’ refers to the
natural gas. Note that the energy is
24-hour major period. Note that the
initially an isolated energy potential,
energy is already passing through the
and external action is required to
environment as a current or flow,
initiate the supply of energy for
irrespective of there being a device to
practical purposes. To avoid using the
intercept and harness this power. Such
ungainly word ‘non-renewable’, such
energy may also be called Green energy supplies are called finite
Energy or Sustainable Energy. supplies or Brown Energy.
Environmental energy
 Energy sources
There are five ultimate primary The flows of energy passing continuously as renewable
sources of useful energy:
i. The Sun. energy through the Earth are shown in Figure 1.2. For
ii. The motion and gravitational
potential of the Sun, Moon and instance, total solar flux absorbed at sea level is about
Earth.
iii. Geothermal energy from 12×1017W. Thus the solar flux reaching the Earth’s surface
cooling, chemical reactions and
radioactive decay in the Earth. is ∼20MW per person; 20MW is the power of ten very
iv. Human-induced nuclear
reactions. large diesel electric generators, enough to supply all the
v. Chemical reactions from
mineral sources. energy needs of a town of about 50 000 people.
However, the global data of Figure are of little value for practical engineering applications, since particular

sites can have remarkably different environments and possibilities for harnessing renewable energy.

• Obviously flat regions, such as Denmark, have little opportunity for hydro-power but may have wind power.

• Yet neighbouring regions, for example Norway, may have vast hydro potential.

• Tropical rain forests may have biomass energy sources, but deserts at the same latitude have none

(moreover, forests must not be destroyed so making more deserts).

Thus, practical renewable energy systems have to be matched to particular local environmental energy flows

occurring in a particular region.